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When to Plant Rosemary in Flagler County, FL

Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.

Flagler County, Florida is in USDA Zone 9a. The average last spring frost is February 5 and the first fall frost is December 17, giving you a growing season of approximately 315 days.

At an elevation of 134 feet, Flagler County receives approximately 54.2 inches of rainfall annually with predominantly sand soil. Summer highs average 99ยฐF, so Rosemary may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Rosemary will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Flagler County, FL (Zone 9a) Year-round
315 days
Last Spring Frost February 5
315 growing days
First Fall Frost December 17

Flagler County Soil Profile

Soil Type

Sand

Soil pH

5.1-5.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (89 days to spare)
Transplant: Jan 29 🍅 Harvest: Apr 23 – Sep 10
Recommended (50%) ✓ Fits season (84 days to spare)
Transplant: Feb 12 🍅 Harvest: May 7 – Sep 24
Safe Start (90%) ✓ Fits season (70 days to spare)
Transplant: Mar 7 🍅 Harvest: May 30 – Oct 17

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Flagler County

How your county's soil matches Rosemary's growing requirements.

Soil pH

Your soil pH (5.1โ€“5.7) is more acidic than Rosemary prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Flagler County warms quickly in spring but drains fast. Rosemary will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Rosemary.

Organic Matter

Organic matter is low (1.6%). Add 2-3 inches of compost before planting Rosemary.

How to Plant Rosemary

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Rosemary

4
successive plantings in your 315-day season

Sow every 9.1 weeks. Last sowing by Jun 20 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Rosemary

Rosemary needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Rosemary Needs Rainfall You Supplement Action
Jan โ€” 2.7" 0" โ„๏ธ Dormant
Feb 1.3" 2.5" 0" โœ… Rainfall sufficient
Mar 1.3" 3" 0" โœ… Rainfall sufficient
Apr 1.3" 2.2" 0" โœ… Rainfall sufficient
May 1.3" 3.7" 0" โœ… Rainfall sufficient
Jun 1.3" 8.8" 0" โœ… Rainfall sufficient
Jul 1.3" 7.7" 0" โœ… Rainfall sufficient
Aug 1.3" 7.4" 0" โœ… Rainfall sufficient
Sep 1.3" 6.9" 0" โœ… Rainfall sufficient
Oct 1.3" 4.7" 0" โœ… Rainfall sufficient
Nov 1.3" 2" 0" โœ… Rainfall sufficient
Dec 1.3" 2.5" 0" โœ… Rainfall sufficient

Water needs are for active growing months only (Febโ€“Dec in Flagler County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Rosemary Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Rosemary needs ~3,152 GDD — county provides 7,663 GDD Excellent fit

Rosemary Planting Timeline โ€” Flagler County, FL

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors February 12 Feb 12 โ€“ Feb 26
Harvest May 7 May 7 โ€“ Sep 24

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Transplant Outdoors
March โ€”
April โ€”
May Harvest
June Harvest
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.3"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

80โ€“180 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

315 days in Flagler County

Growing Tips for Rosemary in Flagler County

Direct sow Rosemary outdoors after February 05 in Flagler County when soil has warmed and frost danger has passed.

Sandy soil in Flagler County dries quickly โ€” mulch Rosemary with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 99ยฐF in Flagler County, provide afternoon shade for Rosemary and water deeply in the morning.

General growing tips

Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rosemary in Flagler County, FL?

Flagler County is in Zone 9a with an average last frost of February 5. Plan your Rosemary planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Flagler County, FL?

Flagler County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 5 and first fall frost is December 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Flagler County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Flagler County, FL. Local conditions may vary. Last updated: April 2026.